Treatment outcomes of extended versus nonextended intensive phase in pulmonary tuberculosis smear positive patients with delayed sputum smear conversion: A retrospective cohort study at primary care clinics in Kota Kinabalu

INTRODUCTION: Delayed sputum smear conversion in patients with smear-positive pulmonary tuberculosis is a crucial problem at primary care clinics in Sabah resulting in poor treatment outcomes. This study aimed to compare the treatment outcomes between extended and nonextended intensive phase treatments among patients with delayed sputum smear conversion and to identify the factors associated with unsuccessful treatment outcomes.

METHOD: This retrospective cohort study was conducted using data from a Malaysian tuberculosis registry, medical records and clinic referral emails from five primary care clinics in Kota Kinabalu from January 2014 to December 2018. A total of 163 patients with delayed sputum smear conversion were selected and divided into cohort groups: 90 patients received 3 months of intensive phase treatment (extended intensive phase), and 73 patients received 2 months of intensive phase treatment (non-extended intensive phase).

RESULTS: Of the 163 patients, 33.7% had unsuccessful treatment outcomes (25.2% had treatment failure; 0.6% died; 3.7% defaulted; and 4.3% transferred out), and 3.7% had relapse. There were no significant differences in the prevalence of unsuccessful treatment outcomes (37.6% vs 28.6%, OR=1.51, CI=0.77-2.94, P=0.226) and relapse (2.2% vs 5.7%, 0R=0.36, CI=0.65-2.04, P=0.404) between the extended and non-extended intensive phase groups. High sputum acid-fast bacilli grade (AFB) at 2 months, drug resistance and lack of directly observed treatment, short-course supervision (DOTS) were associated with unsuccessful treatment outcomes.

CONCLUSION: Extended intensive phase treatment in patients with delayed sputum smear conversion does not prevent unsuccessful treatment outcomes and relapse.